Leak proof carton



5, 1958 J. R. CARPENTER 2,846,132

LEAK PROOF CARTON.

2 Sheets-Sheet 1 Filed Feb. 8, 1957 Ina/6722 27:

\izmes 1? Ca: ryeni'er g- 5, 195.8 J. R. CARPENTER 2,846,132

LEAK PROOF CARTON 2 Sheets-Sheet Filed Feb. 8. 1957 $75265 f5. Carenikr United States Patent LEAK PROOF CARTON Application February 8, 1957, Serial No. 638,970 6 Claims. (Cl. 229-31) This invention relates to cartons for containing comestibles and other products, and is directed more particularly to cartons having sealed corners to guard against leakage when the carton is used for packaging frozen products.

Cartons of the general type with which my invention is concerned are extensively used, many millions being used annually, and are in a highly competitive field in which the cost of production is of importance. My invention is directed to a carton which may readily be formed from a one piece blank of sheet material, such as paper board, and which has corner bellows folds effective for guarding against leakage at the corners of the carton. It is known to provide cartons with corner bellows folds but, in general, the operations required in setting up such cartons from the blanks render the cost of production thereof comparatively high. The carton of my invention is so constructed that it may readily be set up from the blank in high speed machinery with a minimum of folding operations and a corresponding saving in cost of production. More particularly, the blank from which the carton is formed is so constructed that it may be folded and set up in carton form in a single operation in which locking means for retaining the corner bellows folds securely in folded condition is engaged incident to the setting up operation. Further objects and advantages of my invention will appear from the detail description.

In the drawings:

Figure 1 is a perspective view of a carton embodying my invention;

Figure 2 is a plan view of the blank from which the carton of Figure 1 is formed; and

Figures 3 to 6, inclusive, are fragmentary perspective views, on an enlarged scale, illustrating the manner in which the blank of Figure 2 is folded to provide the body of the carton.

The blank of Figure 2 is cut from suitable sheet material, conveniently solid paper board possessing considerable rigidity and resilience. The blank is cut and scored to provide a bottom panel 7, side wall panels 8 and 9, end wall panels 10, corner bellows fold members 11 integrally connecting the adjacent ends of the end wall panels and the side wall panels 8 and 9, a cover panel 12, end flaps 13 and a front cover flap 14. The panels and associated flaps and the bellows fold members 11 are connected together along fold lines indicated by the dot and dash lines and each of the bellows members 11 is provided with a diagonal fold line 15 extending from the intersection of the fold lines for the adjacent side and end wall panels. Preferably a portion of each fold line, indicated at 16, betwen each of the bellow fold members 11 and the corresponding end wall panel 10 is a slit out line to facilitate folding. The side wall panel 9, which is the front wall of the carton, is suitably cut and slit at 17 and 18 for reception of a suitably formed holding tab 19 attached to the lower edge of the front cover flap 14. Each of the side wall panels 10 is proor may be folded in any other suitable manner.

Patented Aug. 5, 1958 vided with a substantially elongated U-shaped cut 20 for reception of a holding tab 21 extending from the lower edge of each of the end flaps 13. Each of the end wall panels 10 is further provided with two pairs of spaced apart slits 22 extending downward from its upper edge and providing between them a pressure tongue 23 integrally attached at its lower end to end wall panel 10, the slits 22 defining between them a notch or opening in the upper edge of end wall panel 10 when the tongue 23 is deflected inwardly of the carton. The diagonal fold line 15 of the respective bellows fold members 11 divides that member into an inner substantially triangular element 24 and an outer element 25 of generally trapezoidal shape having an inclined lower edge corresponding to the fold line 15, the upper edge of element 25 being in the plane of the upper edge of the corresponding side wall panel. Each element 25 is provided, at the edge thereof remote from the corresponding side wall panel, with a projecting locking tab 26 and is slit from its upper edge at 27 to provide a locking tab 28 corresponding to tab 26 and at the formed at the upper portion of element 25 by the slit 27.

The blank of Figure 2 is folded in high speed machinery to produce the carton of Figure 1. The operation of folding and setting up the body portion of the carton is accomplished in a single stroke of a plunger in a folding and setting up machine of known construction. Dur

ing the folding and setting up operation the end wall panels 10 are first erected so as to extend upward from the bottom panel 7, with the bellows fold member 11 in substantially vertical position and the side wall panels and cover panel 12 extending substantially in the plane of the bottom panel 7; as shown in Figure 3. As the folding and setting up operation continues, the side Wall panels are folded upward to vertical position and the bellows fold members 11 are folded along the lines 15 and are then folded over onto the outer faces of the end wall panels 10, as shown in Figures 4 and 5. That completes the bellows folds 11 which respectively comprise the inner elements 24 seating on the outer face of the corresponding end wall panel 10 and the outer element 25 seating on the outer face of the inner element 11 and extending thereabove to the upper edge of end wall panel 10. The locking tongue 29 is then in register with the pressure tongue 23, with the locking tabs 26 and 28 projecting from opposite sides of tongue 29 beyond slits 22, tongues 23 and 29 being properly disposed to that end, as will be understood. In the continued folding and setting up operation the locking tongues 29 are pressed inwardly through the notches or openings provided by the pairs of slits 22, during which the end wall panel 10 adjacent slits 22 is deflected inwardly until tabs 26 and 28 snap past the corresponding areas of the end wall panel 10 so as to be positioned at the inner face thereof. This inward deflection of the locking tongue 29 deflects the pressure tongue 23 inward and, due to its inherent resiliency, it then exerts outward pressure on the tongue 29 effective for holding the locking tabs 26 and 28 seated on the inner face of end wall panel 10 thus effectively locking the corner bellows fold to the end wall panel 10 and effectively guarding against unfolding thereof. That will be clear from Figure 6 which illustrates the end portion of the body of the carton after it has been completely folded and set up in the manner above described. The folding and setting up of the body of the carton is performed in a single operation, as above described, during which the successive steps illustrated in Figures 3 to 6, inclusive, occur as a continuous operation. Upon completion of the body of the carton the cover thereof may be folded in the same machine in a single operation,

As will opposite side of a locking tongue 29 be understood from what has been said, the carton of my invention lends itself to high speed machine operation and may be produced' ,at comparatively low cost to meet competitive conditions. In that connection, the provision of the corner bellows fold locking means disposed as shown renders the carton of my invention particularly suitable for large volume production by! highv speed folding and setting up machinery, and' the dispo sition of the bellows folds at the outer faces of the end wall panels renders the cartonof my invention well suitedfor folding and settingup byv plunger means in a high speed machine of known typespreviously referred to.

The carton-of my invention is particularly suitable-for containing frozen food of various sorts, and the corner bellows folds effectively prevent leakage at the corners-of the body of the carton. The loaded carton is closed by the cover panel 12 held in closed position by insertion of tab 19' through cuts 17 and 18 and the insertion of tabs 21 through the cuts 20,.as will be understood. Changes in' detail may be resorted to without departing from the field and scope of my invention, andl intend to include all such variations, as fall within the scope of the appendedclaims, in this application in whichthe preferred form only of my invention has been disclosed.

I claim:

1}. A carton formed of sheet material posssessingr substantial rigidity and resilience such as paper board and comprising, a bottom panel, side and end wall panels extendingupward from said bottom panel, corner bellows folds joining said side and end wall panels and each having a first element seating on one face of one of said wall panels and asecond element seating on said first element, said second. element extending upward beyond said first element approximately to the upper edge of said one wall panel,v the latter having two slits extending from its upper edge defining between them a notch at the upper edge of saidone wall panel and at pressure tongue corresponding. to said notch and integrally attached to said one wall. panel and free for deflection away from said one face of said one wall, and a locking tongue on said second element provided adjacent its upper edge and at its sides with two locking tabs of a width to snap through said notch incident to deflection of said locking tongue through said notch, said tongue being, flexed beyond said onewall panel through said notch with said tabs seating on the other face of said one wall panel and in cooperation therewith restraining said second element against movement away from said one wall, said pressure tongue being flexed away from said one wall panel by said locking tongue and by its inherent resiliency urging the latter toward. said one wall panel with said tabs seating. thereon.

2. A carton formed of sheet material possessing substantial rigidity and resilience such as paper board and comprising, a bottom panel, side and. end wall panels extending upward from said bottom panel, corner bellows folds joining said side and end wall panels and each having a first element seating on the outer face of the contiguous end wall panel and a second element seating on said first element, the inner ends of said bellow-s folds being spaced apart, said second element extending upward beyond said first element approximately to the upper edge of said end wall panel, the latter having two slits extending from its upper edge defining between thema notch at the upper edge of said end wall panel adjacent an upper corner thereof 'and a pressure tongue corresponding to said notch and integrally attached to said end wall panel, said pressure tongue being' free for inward deflection away from the outer face of saidend wall panel, and a locking tongue on said second member provided adjacent its upper edge and at its sideswithtwo relatively narrow locking tabs ofa width to snap throughsaid notch, said tongue being flexed inward through said notch with said tabs seating, on the inner face of saidend'wallpanel'and in cooperation therewith restrain-1 4, ing said second element against outward movement,,said pressure tongue being flexed inward and its inherent resiliency urging said locking tongue toward said end wall panel with said tabs seating thereon.

3. A carton formed of sheet material possessing substantial rigidity and resiliency such as paper board and comprising, a bottom panel; side and end wall panels extending upwardgfrom sa'id bottom panehcorner bellows folds joining said side and end wall panels and seating on the outer face'ofrsaid" end wall panels at the upper corner portions thereof, said end wall.v panels having two slits extending from the upper edge of their respective corner. portions'id'efi'ning between them a notch and a corresponding pressure tongue integrally attached to said end wall panel andfree for deflection inwardly thereof, and a locking tongue on the respective bellows folds provided adjacent its upper edge and at its sides with two relatively narrow locking tabs disposed substantially in theplane: of said locking. tongue and adapted to" besnapped' through said notch' incident to deflection there-- throughof said locking tongue, the latter being deflected through said notch with said tabs extendingsubstantially inthe plane of said. locking tongueand held by the inherent resiliency thereof seated on*the inner face of said end wall panel, said pressure tongue being defiectedin-- ward and, by its inherent resiliency exerting outward pressure on said locking tongue. supplementary to the outward pressure: of. the latter for holding said tabs seated onthe inner face of said end wall panel in-pressu're" contact therewithi 4. Av carton formed of sheet material possessingsub-- stantial rigidity and resiliency such as paper board and comprising, a-bottom panel, side and end wall panels extendi-ngtupwardfromsaidabottom panel; corner bellows folds joining saidrsidei and end wall panels respectively comprising a first substantially triangular element seat ing-on the outer face of thetendwall paneland asecond substantiallytrapezoidal' element seating on said first element and extending; thereabove to approximately the upper edge of said end wall panel, the latter having two through said notch with said tabs extendingsubstantiilly in the plane of said locking tongue and held by the inherent resiliency thereof seated on the inner face of said=end wall panel, said pressure tongue being deflected inward and by its inherent resiliency exerting outward pressure on said locking tongue supplementary to the outward pressure ofthelatter for holding said tabs-seatcd -on the inner face of said end wall panel in pressure contact therewith.

5. A carton formed of: sheet material possessing substantial rigidity and" resilience such as paper board and comprising. a bottom: wall member, side and end wall members-extending upward from said bottom wall member, cornerbellows folds joining said side and end wallmembers and each: having a first element seating on the outer face oh the contiguous end wall member and a second element seating on said first element, said end wall member comprising a portion cut to provide openings therein above and adjacent saidbellows folds and pressure tongues corresponding to said openings and in tegnally attached tosaid end: wall member, and locking tongues extendingfrom. said-second elements of said lid-'- lows folds upward beyond said: first elements thereof, said. locking tongues being provided at the sides there ofi with locking tabs ofawidth to'snap through said openings--incideut tcsdeflecting 'oii-saiditonguesinward throughsaid openings, said tongues being deflected inward through said openings with said tabs seating on said portion of said end wall member at the sides of said openings and in cooperation with said end wall member restraining said second elements of said bellows folds against outward movement, said pressure tongues being deflected inward and the inherent resiliency thereof urging said locking tongues toward said portion of said end Wall member with said locking tabs seating on the latter.

6. A carton formed of sheet material possessing substantial rigidity and resilience such as paper board and comprising a bottom Wall member, side and end Wall members extending upward from said bottom Wall member, corner bellows folds joining said side and end wall members and each having a first element seating on the outer face of the contiguous end wall member and a second element seating on said first element, said end wall member comprising a portion cut to provide openings therein adjacent said bellows folds, and locking tongues extending from said second elements of said bellows folds, said tongues being provided at the sides thereof with locking tabs of a width to snap through said openings incident to deflecting of said tongues inward through said openings, said tongues being deflected inward through said openings with said tabs seating on said portion of said end wall member at the sides of said openings and in cooperation with said end wall member restraining said second elements of said bellows folds against outward movement.

References Cited in the file of this patent UNITED STATES PATENTS 1,210,952 Krueger Jan. 2, 1917 2,499,436 Whitfield Mar. 7, 1950 2,682,988 Van Rosen July 6, 1954 

